He also said he has seen overall drive quality falling over time as the result of price competition in the industry. He urged customers to begin tracking disk drive records "and to make a big noise with the vendor" to force them to review their testing processes.

FC vs. SATA

While a general reputation for increased reliability (as well as higher performance) is one of the reasons FC drives cost as much as four times more per gigabyte than SATA, "We had no evidence that SATA drives are less reliable than the SCSI or Fibre Channel drives," said Gibson. "I am not suggesting the drive vendors misrepresented anything," he said, adding that other variables such as workloads or environmental conditions might account for the similar reliability finding.

Analyst Brian Garrett at the Enterprise Storage Group in Milford, Mass., said he's not surprised because "the things that can go wrong with a drive are mechanical -- moving parts, motors, spindles, read-write heads," and these components are usually the same whether they are used in a SCSI or SATA drive. The electronic circuits around the drive and the physical interface are different, but are much less prone to failure.

Vendors do perform higher levels of testing on FC than on SATA drives, he said, but according to the study that extra testing hasn't produced "a measurable difference" in reliability.